Old Mutual dictating about people's policies

I have three policy with Old Mutual on my personal level. Yesterday I asked them to cancel one of my investment policy, today they say I cannot cancel it because the money in it is over R15000. Are they forcing people to keep paying for policy even if you can't afford paying it? I need this policy cancel with immediate effect and the balance pay back into my account. I find this very disturbing and dictating what people must be with their policies